This invention relates to hydrants or valves attached to municipal water systems, and in particular to a device for simplifying the flushing of portions of water systems.
The need for periodically flushing portions of water systems, particularly dead-ends in the systems, has been recognized for many years, as shown for example in Lazenby III, U.S. Pat. No. 4,756,479. A summary of many of the problems requiring such flushing, as well as of the traditional solutions to those problems, is contained in my co-owned U.S. Pat. No. 5,201,338. More recently, such flushing operations have been automated, as described in McCarty, U.S. Pat. No. 5,921,270. The McCarty patent is owned by a company related to the assignee of the present invention. A similar approach is described in Newman, U.S. Pat. Nos. 6,035,704 and 6,358,408. Other approaches are shown in Poirer, U.S. Pat. No. 6,062,259, and Esmailzadeh, U.S. Pat. No. 6,467,498, and in Taylor et al, published applications US 20040252556, US 20040238458, US 20040238037, and US 20040238028.
Although the prior art systems have met with success, the complexity of the systems, the time and effort required to install and use them, the difficulties attendant to removing and servicing them, and their consequent expense have limited their use.
In accordance with another approach to providing automatic flushing, described in my co-owned U.S. Pat. No. 6,820,635, a portable device is installed externally to the outlet of an existing hydrant. This approach requires keeping the hydrant's manual valve open, and the device must be removed from the hydrant in freezing weather.
It is important to maintain water quality, including chlorine residuals, at dead ends of municipal water systems regardless of how the line is purged. If it is flushed infrequently, a large amount of water must be flushed from the system; if it is flushed frequently, then a much smaller amount of water need be expelled.